Figure 1-10. Power Distribution - Dell Precision 400 Service Manual

PWRGOOD
PSON#
+5 VFP
+5 VDC
system
–5 VDC
power supply
+12 VDC
–12 VDC
P7
+3.3 VDC
P2
internal
1
hard-disk drive
P3
internal
1
hard-disk drive
P4
3.5-inch
diskette drive
P5
optional
drive
P6
optional
drive
P9
optional
2
drive
1
When a third SCSI hard-disk drive is installed (mini tower computers only), a Y-cable from
P2 connects the first two devices and P3 connects the third SCSI hard-disk drive.
2
The third optional drive bay (5.25-inch) is available only in mini tower computers.

Figure 1-10. Power Distribution

keyboard
controller
+3.3 VDC
power
management
logic
P1
POWER1
PSON#
+5 VFP
+5 VDC
–5 VDC
+12 VDC
–12 VDC
POWER2
main memory
sockets
DIMM_A
DIMM_B
DIMM_C
DIMM_D
2.5-V 1.5-V
converter converter
SLOT1_PRI
+1.8–2.8 VDC
+2.5 VDC
+1.5 VDC
SLOT1_SEC
+1.8–2.8 VDC
+2.5 VDC
+1.5 VDC
system board
battery
RTC/
NVRAM
+12 VDC
–12 VDC
RISER
+5 VDC
–5 VDC
+12 VDC
–12 VDC
+12 VDC
FAN
+5 VFP
PANEL
+5 VDC
FUS
+5 VDC
USB
FUS
+5 VDC
KYBD
+5 VDC
MOUSE
processor
core regulator
riser board
PCI1
+5 VDC
through
PCI5
+5 VDC ISA1,
ISA2
–5 VDC
+12 VDC
–12 VDC
System Overview 1-13